Conventionally, a rolling sphere method has been known as a simulation model relating to lightning.
The rolling sphere method is a common lightning shielding model based on an electro-geometric model. A probability of being struck by lightning is derived only from a geometrical shape of an object and a peak value of current, i.e., a parameter of lightning. In the rolling sphere method, a striking distance (distance over which a lightning finally jumps) is uniquely determined from the peak value of current, and any object within a range of the striking distance is considered to be struck by lightning (for example, see Patent Citation 1 below).